News under pressure? Politicization of scientific expertise in German mainstream news during COVID-19

Using a corpus from ten German outlets during COVID-19, we examine how mainstream media translated scientific expertise into political debate. We define politicization narrowly as coverage in which conflict or controversy, partisan alignment, and communicated uncertainty about expert claims co-occur. Combining named-entity recognition for political and expert actors with word-embedding measures around policy-intervention terms, we estimate mixed-effects models of politicized coverage. Politicization was episodic, peaking at major policy junctures, and outlets differed more from one another than a convergence perspective would predict. Biomedical coverage showed a higher baseline of politicization but only modest ideological differences among centrist, centre-left, and centre-right outlets. By contrast, in non-biomedical coverage of policy trade-offs involving the economy, schooling, and civil liberties, centre-right outlets more often used the conflict-partisan-uncertainty configuration, while centre-left outlets remained close to the centrist benchmark. These findings indicate that editorial routines, brand positioning, and the disciplinary locus of expertise shape when and how science is politicized. The study contributes to research on how scientific authority is contested in public debate by showing that politicization is not a uniform media-system response to crisis, but a domain- and outlet-specific translation of uncertain evidence into collective choices under conditions of public urgency and political contestation.